Traction device and associated lifting mechanisms

ABSTRACT

In one embodiment, an ambulatory traction device includes a first support configured to be positioned on a user&#39;s body and a second support configured to be positioned on the user&#39;s body spaced apart from the first support such that a portion of the user&#39;s body is positioned between the first and second supports. The traction device also includes one or more lifting mechanisms that each couple the supports and apply a decompressive force to the portion of the user&#39;s body when the supports are positioned on the user&#39;s body. Each lifting mechanism includes a sleeve having a non-circular cross-section and operable to contain a fluid. Each lifting mechanism also includes a piston configured to move within the sleeve in response to an increase in pressure within the sleeve.

RELATED APPLICATIONS

This application claims the benefit of Provisional Application No.60/272,821 filed Mar. 1, 2001.

This application is a continuation of U.S. patent application Ser. No.09/875,332 entitled “Lifting Mechanism for a Traction Device,” filedJun. 5, 2001 now U.S. Pat. No. 6,533,740 B2.

TECHNICAL FIELD OF THE INVENTION

This invention relates to the field of medical devices, and moreparticularly to a traction device and associated lifting mechanisms.

BACKGROUND OF THE INVENTION

Humans have long dealt with the pain, aggravation and loss ofproductivity arising from spinal injuries, particularly those to the lowback. Most people at some point in their lives will be incapacitated bylower back pain which has become the second leading cause of pain nextto headaches. The relative ease with which injuries to the spine andsupporting musculature are incurred, as well as the debilitating effectsof even slight injuries, merely adds to the overall severity of theproblem of dealing with spinal injuries. The forms of treatment varyover the length of time that the patient experiences pain. Eightypercent of low back pain suffers will heal over six weeks with minimalintervention. However, the remaining twenty percent of sufferers createthe greatest challenges and cost to the medical system. After the acutephase, surgical intervention or more invasive forms of treatment may beselected. Minimal or non-invasive treatment methods are howeverpreferred by patients before electing to surgical methods.

SUMMARY OF THE INVENTION

According to the present invention, disadvantages and problemsassociated with previous medical devices for treating joints have beensubstantially reduced or eliminated.

In one embodiment, an ambulatory traction device includes a firstsupport configured to be positioned on a user's body and a secondsupport configured to be positioned on the user's body spaced apart fromthe first support such that a portion of the user's body is positionedbetween the first and second supports. The traction device also includesone or more lifting mechanisms that each couple the supports and apply adecompressive force to the portion of the user's body when the supportsare positioned on the user's body. Each lifting mechanism includes asleeve having a non-circular cross-section and operable to contain afluid. Each lifting mechanism also includes a piston configured to movewithin the sleeve in response to an increase in pressure within thesleeve.

Certain embodiments of the present invention may provide one or moretechnical advantages. For example, certain embodiments provide atraction device that may be worn by a user to reduce the compressiveforces on the user's spine by transferring the user's upper body weightoff of the spine to the user's hips. In particular, the decompressiveforces generated by the device may be concentrated on the lower spine ofthe user, an area that may be commonly injured due to compressiveforces. The traction device may also provide stabilization of the torsoto prevent additional compressive forces in the spine due to bending andlifting by the user. Moreover, traction devices of the present inventionmay be used in association with other joints of the body, such as theknee or neck. Furthermore, particular embodiments provide a tractiondevice that is ambulatory, meaning that the device is portable andwearable during the user's daily activities. This ambulatory nature ofthe device provides more convenience to the user and causes less impacton the user's daily activities than previous treatment techniques.

The decompressive force applied to the user's spine (or other joint) maybe applied using one or more lifting mechanisms coupled between twosupport belts that are wrapped around the user's torso and hips (oraround other body parts, if used in association with other joints). Incertain embodiments, these lifting mechanisms are piston-type liftingmechanisms that have a substantially elliptical cross-section (unliketraditional piston-type lifters, which have a circular cross-section).This substantially elliptical cross-section reduces the profile of thelifting mechanisms against the user's body thus minimizing interferencewith the environment while the user is performing the tasks of dailyliving. This low profile is more aesthetically appealing and providesmore comfort to the user than would similar cylindrical liftingmechanisms. This low profile also allows the traction device to be moreeasily worn under other clothing, if desired.

Certain embodiments may provide all, some, or none of these advantages.Certain embodiments may provide one or more other technical advantages,one or more of which may be readily apparent to those skilled in the artfrom the figures, description and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present invention andthe features and advantages thereof, reference is made to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a schematic diagram showing an example spinal traction devicebeing worn by a user;

FIG. 1B is a cross-sectional drawing of a portion of the spinal tractiondevice of FIG. 1B, showing example locations for lifting mechanismsassociated with the traction device;

FIG. 1C is a cross-sectional drawing of a portion of the spinal tractiondevice of FIG. 1B, showing example locations for an alternativeembodiment of the invention;

FIG. 2 is a schematic diagram illustrating in more detail portions ofexample top and bottom belts of the spinal traction device of FIG. 1A;

FIG. 3 is a schematic drawing with portions cut away showing in moredetail one of the example lifting mechanisms of the spinal tractiondevice of FIG. 1A;

FIGS. 4A through 4D illustrate various views of an example liftingmechanism for use in a spinal traction device;

FIG. 5 illustrates an example valve assembly of a spinal tractiondevice;

FIGS. 6A and 6B illustrate an example back belt included in a supportbelt of a spinal traction device; and

FIG. 7 illustrates another example back belt included in a support beltof a spinal traction device.

FIG. 8 is a schematic diagram illustrating a portion of the spinaltraction device of FIGS. 1A through 1D, showing portions of one of thebelts;

FIG. 9A is a top view of an example support belt and length adjustmentmechanism combination in a first, unadjusted position;

FIG. 9B is a top view of the combination of FIG. 9B in a adjustedposition; and

FIG. 9C is a top view of a support belt after removal of the adjustmentmechanism of FIGS. 9A and 9B.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1A is a schematic diagram illustrating an example traction device10 being worn by a user 12. In this embodiment, traction device 10applies decompressive forces to the spine of user 12, which transfersbody weight from the upper torso to the hips of user 12 and preventscompression and aggravation of lower back spinal conditions. In oneembodiment, the offloading forces are concentrated specifically on thelower spine, rather than across the entire spine. This effect is createdby decompressive forces pushing upward and downward on the lower spine.These decompressive forces are created by traction device 10, asdescribed below. In other embodiments, tracking device 10 may also bemodified to create tension in other portions of the body, such as thefemur.

Spinal traction device 10 includes an upper support belt 14 and a lowersupport belt 16; however in other embodiments, the decompression forcesmay be generated through various combinations of one or more belts.Support belts 14 and 16 may be formed in any suitable manner that allowspositioning around the body of a user and transferring of adecompressive force to user 12. Example details of one embodiment ofbelts 14 and 16 are described in greater detail below in conjunctionwith FIG. 2.

Spinal traction device 10 also includes one or more lifting mechanisms18. Lifting mechanisms 18 generate a decompressive, or tensile, forcethat may be transferred to the spine of user 12 through support belts 14and 16. Lifting mechanisms 18 are coupled to a valve assembly (FIG. 5)to control pressurization of lifting mechanisms 18. In one embodiment,lifting mechanisms 18 are coupled serially to the valve assembly;however, they may be coupled to the valve assembly in a parallel orother suitable fashion. Lifting mechanisms 18 are disposed withinpouches 19 connected to lower support belt 16 and pouches 21 connectedto upper support belt 14. Example locations about the circumference ofbelt 16 of lifting mechanisms 18 are shown more clearly in FIGS. 1B and1C. Coupling of lifting mechanisms 18 to support belts 14 and 16 isdescribed with reference to FIG. 3. Example details associated with oneparticular embodiment for lifting mechanism 18 are described in greaterdetail below in conjunction with FIGS. 4A-4D. However, in theillustrated embodiment, lifting mechanisms 18 are fluidic (for example,pneumatic or hydraulic) devices that create a decompressive, or tensile,force through fluid pressure. Lifting mechanisms 18 may also bemechanical devices. When pressurized, lifting mechanisms 18 push upwardon support belt 14 and downward on support belt 16, resulting in adecompressive force on the spine of user 12.

A proper fitting of spinal traction device 10 about the body of user 12is important. Fitting is accomplished, in part, through a pair oflocking devices 20, one located on upper support belt 14 and one locatedon lower support belt 16 and through a common strap 22. Common strap 22forms a part of both upper support belt 14 and lower support belt 16 andtherefore allows uniform adjustment to both belts at the same time.Locking mechanisms 20 include a plurality of notches 24 and a latch 26for locking mechanism 20 in place at a desired notch location. Lockingmechanisms 20 may, however, be replaced with any suitable mechanism forlocking belts 14 and 16 into a desired location, such as snaps, hook andloop type fasteners and other suitable fasteners Common strap 22 isdescribed in greater detail below with reference to FIG. 2.

In operation, user 12 places spinal traction device 10 around his waistand adjusts belts 14 and 16 using common strap 22 to a desired tensionaround his waist. Common strap 22 facilitates obtaining uniformtightness of both support belts 14 and 16. User 12 may then lock belts14 and 16 in place using locking mechanisms 26. To apply traction to thespine of user 12, a fluid is supplied to lifting mechanisms 18 to causelifting mechanisms 18 to expand pushing belt 14 upward and belt 16downward. Because support belts 14 and 16 are tightly wrapped around thebody of user 12, this decompressive force is transferred to the user'sbody and hence his spine. This relieves stress on the spine.

Traction device 10 may be portable and wearable during everydayactivities. Thus, device 10 may be applied at home, work, play or duringtravel and at user's 12 convenience. Therefore, a user is more likely tocomply with therapy guidelines much more readily than if user 12 wasrequired to travel to a clinic for therapy. The amount of forcegenerated by the lifting mechanisms 18 may be controlled by the patientthrough a manual inflation device, or valve assembly, described ingreater detail in conjunction with FIG. 5, or may alternatively becontrolled with another suitable control device. In one embodiment,pressures generated within lifting mechanisms 18 offload approximately50% of the body weight of user 12. A relief valve (not explicitlyshown), may be provided to prevent overinflation. Such a relief valvemay be situated such that user 12 may instantly relieve the pressure inlifting mechanisms 18 at any time. Spinal device 10 may also stabilizethe torso, while still allowing flexibility. This stabilization preventsadditional compressive forces in the spine due to bending and lifting.

FIGS. 1B and 1C are partial cross-sectional drawings through lines 1B—1Band 1C—1C, respectively, of FIG. 1A showing more clearly examplelocations for lifting mechanisms 18. FIG. 1B illustrates examplelocations for lifting mechanisms for normal spinal decompression use. Asillustrated, four lifting mechanisms are used, with two in the generalback region of user 12 and two located towards the front of user 12.This configuration allows application of a decompressive force to thespine yet allows user 12 to perform daily operations without unduehindrance. FIG. 1C illustrates a different configuration that alsorestricts motion of user 12 from side to side, in addition to placingthe spine of user 12 into traction. This may be particularly useful fortreating scoliosis. Scoliosis is a condition where the spine curves toone or two directions in the thoratic and/or lumbar region. Thevertebrae of the spine are twisted or tilted, which causes the ribs toprotrude to one side. By locating lifting mechanisms 18 towards the sideof user 12, side-to-side motion by user 12 may be restricted and astraightening force may be applied to the spine to treat the spinalcurvature effects of scoliosis. Although four lifting mechanisms areillustrated in both FIGS. 1B and 1C, any suitable number of liftingmechanisms may be used.

FIG. 2 is a schematic diagram of spinal traction device 10 showingadditional details of lower support belt 16 and upper support belt 14.Upper support belt 14 is formed from a back belt 28 and a pair of frontbelts 30. Some portions of front belt 30 are not illustrated in FIG. 2for clarity of illustration. Front belt 30 is formed with a plurality ofholes 32 allowing selective adjustment of the size of upper belt 14. Inconjunction, back belt 28 includes a plurality of slits 35 for engagingfront belt 30 and a hole 34 for meshing with holes 32 in front belt 30.Front belt 30 and back belt 28 may be locked together through a rivet orother connector placed through a desired hole 32 and hole 34 on frontbelt 30 (not explicitly shown in FIG. 2). Surrounding front belts 30 andback belt 28 is an outer sleeve 31. Portions of outer sleeve 31 are cutaway in FIG. 2. Outer sleeve 31 provides an attractive look to supportbelt 14 and also may provide cushioning comfort to user 12. Outer sleeve31 may be formed from fabric or other suitable material and may beformed in a plurality of sections to facilitate selective access to backbelt 28 and front belts 30 for adjustment.

Back belt 28 includes a strap 202 intermeshed between two plates 204.Back belt 28 is a generally rigid member in the direction of generalizedsupport (up or down in this example) and is disposed within outer sleeve31 of belt 14. As described in greater detail below, a force applied toupper back belt 28 from lifting mechanisms 18 is transferred to outersleeve 31 and therefore the spine of user 12. Front belts 30 are alsogenerally rigid in the direction of support and may be formed fromplastic or other suitable material.

Top plate 202 and plates 204 are described in greater detail below withrespect to FIGS. 6A and 6B; however particular portions associated withapplication of a decompressive force to belts 14 and 16 are describedhere. The plate 204 that is positioned to the exterior of strap 202 isformed with notches 36 a. Notches 36 a couple to portions of liftingmechanisms 18 and facilitate transferring of a decompressive force fromlifting mechanisms 18 to upper belt 14. Plate 204 is generally rigid inthe direction of support such that it may transfer a force resultingfrom lifting mechanisms “pushing” it. Plate 204 may be formed from anysuitable material that allows transferring of force from liftingmechanisms 18 to a belt 14; however in one embodiment, plate 204 isformed from plastic. A notch 36 a may have a substantially semi-circularshaped side curving in a direction generally away from lifting mechanism18. Plate 204 is also be formed with slots 36 b, each of which at leastpartially surrounds the corresponding notch 36 a. Each slot 36 b definesa portion of plate 204 that, because of slot 36 b formed in elate 204,is enabled to rotate generally transverse to the surface of plate 204that is adjacent the user's body (i.e. rotate generally toward and awayfrom the user). As shown, slots 36 b may be substantially semi-circularand may curve in a direction generally away from lifting mechanism 18.Ends of slots 36 b may be enlarged into substantially circular openings.

Lower support belt 16 is similar to upper support belt 14. Lower supportbelt 16 includes a back belt 40 and a pair of front belts 42. Back belt40 and front belts 42 are substantially similar to upper back belt 28and front belt 30 and include a plate 44 and a strap 46; however, plate44 is formed with notches 37 a facing downward rather than upward toallow transference of force from lifting mechanisms 18 in a downwarddirection. A notch 37 a may have a substantially semi-circular shapedside curving in a direction generally away from lifting mechanism 18,opposite the direction in which notch 36 a curves. Similar to elate 204,plate 44 is also formed with slots 37 b, each of which at leastpartially surrounds the corresponding notch 37 a. Slot 37 b defines aportion of plate 44 that, because of slot 37 b formed in plate 44, isenabled to rotate generally transverse to the surface of plate 44 thatis adjacent the user's body (i.e. rotate generally toward and away fromthe user). As shown, slots 37 b may be substantially semi-circular andmay curve in a direction generally away from plate 44. Ends of slots 37b may be enlarged into substantially circular openings.

Also shown more clearly in FIG. 2 is common strap 22. Common strap 22connects to both upper belt 14 and lower belt 16, allowing commonadjustment of spinal traction device 10 about the body of a user. Inthis example, hook and loop type fasteners 48, commonly known asVelcro™, are disposed on common strap 22 to secure strap 22 into place.

One of holes 32 in front belt 30, denoted by reference numeral 50, andone of holes 32 in front belt 42, denoted by reference numeral 52, arealso illustrated in FIG. 3.

FIG. 3 is a schematic diagram of portions of spinal traction device 10with portions cut away showing additional details of coupling of liftingdevice 18 with upper belt 14 and lower belt 16. This figure may beoriented with respect to FIG. 2 by holes 50 and 52. As illustrated,front belt 30 includes a notch 56 a, analogous to notches 36 a, andfront belt 42 includes a notch 57 a, analogous to notches 37 a. Liftingdevice 18 is coupled between belts 14 and 16 through notches 56 a and 57a and clips 132, respectively, of lifting mechanisms 18. Access tonotches 56 a and 57 a is provided through pouches 21 and 19, shown inFIG. 1A. A notch 56 a, 57 a may have a substantially semi-circularshaped side curving in a direction generally away from lifting mechanism18, opposite the direction in which the other notch 57 a, 56 a curves.Front belt 30 also includes a slot 56 b, analogous to slots 36 b, andfront belt 42 also includes a slot 57 b, analogous to slots 37 b, eachof which at least partially surrounds the corresponding notch 56 a or 57a, respectively. Slot 56 b, 57 b defines a portion of the correspondingfront belt 30, 42 that, because of slot 56 b, 57 b formed in front belt30, 42, is enabled to rotate generally transverse to the surface offront belt 30, 42 that is adjacent the user's body (i.e. to rotategenerally toward and away from the user). As shown, slots 56 b, 57 b maybe substantially semi-circular and may curve in a direction generallyaway from the corresponding front belt 30, 42. Ends of slots 56 b, 57 bmay be enlarged into substantially circular openings. Additional detailsof lifting mechanism 18 are described in greater detail below inconjunction with FIGS. 4A through 4D.

In operation, in order to apply a decompressive force between upper belt14 and lower belt 16, lifting device 18 is pressurized causing adownward force on the lower end of lifting device 18, as denoted byreference numeral 58 and an upward force on the upper end of liftingdevice 18, as denoted by reference numeral 60. This in turn generatesforces in belt 30 and front belt 42 in opposite directions. Liftingmechanisms 18 may also be coupled between belts 14 and 16 at notches 36a and 37 a in plates 204 and 44. Restriction of lifting mechanism 18therefore results in applying a decompressive force to the spine of user12 through belts 14 and 16. Additional details of examples of suitablelifting mechanisms 18 are described in greater detail below inconjunction with FIGS. 4A through 4D.

FIGS. 4A through 4D illustrate various views of an example liftingmechanism 18 for use in spinal or other traction device 10. FIG. 4A isan exploded view of lifting mechanism 18, FIGS. 4B and 4C are differentisometric views of an assembled lifting mechanism 18, and FIG. 4D is aside view of lifting mechanism 18 illustrating internal components oflifting mechanism 18 using broken lines. Although lifting mechanisms aredescribed, it should be understood that other types of supportmechanisms may be used. For example, static support mechanisms may beused that do not extend (unlike lifting mechanisms 18), but that simplyprovide static support. As described above, one or more liftingmechanisms 18 may be coupled between support belts 14 and 16 or anyother suitable supports (for example, between pins positioned in auser's bones on either side of a joint) and extended to provideseparation of support belts 14 and 16, thus reducing the compressiveforces applied to one or more of the vertebrae of user's spine (or anyother suitable joint). As is illustrated, example lifting mechanism 18has a substantially elliptical cross-section. The term “elliptical” ismeant to include all noncircular ellipses, ovals, “egg” shapes, “bean”shapes, and any other similar shapes. When lifting mechanism 18 ispositioned as a part of traction device 10, this substantiallyelliptical cross-section provides greater comfort to the user and has alower profile against the user's body than would a similar liftingmechanism having a cylindrical cross-section. Furthermore, other shapesthat conform to the user's body may also be used. However, as describedbelow, the use of such substantially elliptical or other non-circularcross-sections present problems that are not associated with acylindrical cross-section.

Lifting mechanism 18 includes a piston having a piston rod 102 and aflange 104 that is inserted into a sleeve 106. In the illustratedembodiment, piston rod 102, flange 104, and sleeve 106 each have asubstantially elliptical cross-section. However, any other appropriateshape may be used for one or more of these components. For example,flange 104 and sleeve 106 may have substantially ellipticalcross-sections and piston rod 102 may have a circular or otherappropriate cross-section. Flange 104 is configured such that itconforms to the inside of sleeve 106 and may slide inside sleeve 106. Apiston ring 108 may be positioned around the perimeter of flange 104 toform a seal between flange 104 and sleeve 106. A groove 110 may beformed around the perimeter of flange 104 to provide a seating forpiston ring 108. Piston ring 108 may have a rectangular cross-section, acircular cross-section, or any other appropriate type of cross-section.Furthermore, piston ring 108 may be fabricated from rubber or any otherappropriate material.

Since sleeve 106 has a non-circular cross-section, if the interior ofsleeve 106 is pressurized to effect the movement of piston rod 102 (asdescribed below), stresses will be developed in sleeve 106 and givesleeve 106 the tendency to deform into a cylindrical shape. This isundesirable since it may induce leakage between sleeve 106 and pistonring 108. Therefore, sleeve 106 may be fabricated from a metal, such asaluminum, or another appropriate material to withstand these stressesand prevent such deformation. In the example embodiment, sleeve 106 hasopenings at either end and thus does not form an airtight chamber intowhich air or any other appropriate fluid may be inserted to move pistonrod 102. Therefore, to form an airtight chamber, a housing is formedaround sleeve 106. The housing includes a housing bottom 112 which fitsover one end of sleeve 106 and a housing top 114 which fits over theother end of sleeve 106 and contacts housing bottom 112. Housing top 114also provides an opening 116 through which piston rod 102 may beextended. A housing ring 118 may be inserted into housing bottom 112 toprovide a seal between sleeve 106 and housing bottom 112 to prevent orreduce the leakage of air or other fluids from sleeve 106. A lower edge120 of housing top 114 may be sonically welded to a upper edge 122 ofhousing bottom 112, although housing bottom 112 and housing top 114 maybe coupled in any other appropriate manner to form a substantiallyairtight enclosure. Housing bottom 112 and housing top 114 may befabricated from plastic or any other suitable material. Furthermore,housing top 114 may be eliminated in certain embodiments and sleeve 106may have a partially enclosed first end and be bonded with housingbottom 112 at a second end. However, housing top 114 may be used whenbonding between sleeve 106 and housing bottom 112 is infeasible due tothe use of differing materials to fabricate sleeve 106 and housingbottom 112.

In particular embodiments, piston rod 102 may be hollow such that acavity 124 extends from one end of piston rod 102 to the other. Cavity124 extends through flange 104 such that air or another fluid in sleeve106 may travel through piston rod 102 in cavity 124. Therefore, a pistonrod top 126 is coupled to the end of piston rod 102 opposite flange 104to prevent this air or other fluid from escaping from sleeve 106 throughpiston rod 102. Piston rod top 126 may be sonically welded to piston rod102 or coupled to piston rod using any other suitable technique. As withpiston rod 102, piston rod top 126 may be fabricated from plastic or anyother appropriate material. Cavity 124 is provided in particularembodiments so that a spring 128 or other appropriate elastic member maybe used to connect housing bottom 112 and piston rod top 126. Spring 128is used to provide a force to retract piston rod 102 into sleeve 106when a sufficient air or other fluid pressure does not exist in sleeve106 to counteract the retraction force generated by spring 128, such aswhen traction device 10 is not in use. Housing bottom 112 and piston rodtop 126 may each include a hook point 130 which may be used to attachspring 128 to housing bottom 112 and piston rod top 126. Alternatively,any other appropriate attachment points located in any other suitablepositions may be used. Housing bottom 112 and piston rod top 126 mayalso include clips 132 for coupling lifting mechanism 18 to supportbelts 14 and 16, as described above.

As shown in FIG. 4C, housing bottom 112 also includes one or more inlets134 through which air or any other appropriate fluid may be pumped intoand released from sleeve 106. For example, inlets 134 may be configuredsuch that a hose from an associated pump may be coupled to inlets 134.Using such a pump, air or another fluid may be pumped into sleeve 106until a sufficient amount of pressure is exerted against a bottom face136 of flange 104 (shown in FIG. 4A), and against piston rod top 126 ifpiston rod 102 is hollow to cause flange 104 to move away from housingbottom 112 and thus for piston rod 102 to extend out from housing top114. Air or any other appropriate fluid may be pumped into sleeve 106through inlets 134 until piston rod 102 is in an appropriate position.As described above, multiple lifting mechanisms 18 may be coupledbetween support belts 14 and 16, and the piston rod 102 of each liftingmechanism 18 may be extended such that appropriate spacing is maintainedbetween support belts 14 and 16 and an appropriate force is applied toplace the user's spine or other joint in traction. Once this appropriateposition and force are reached, the pressure against flange 104 (andpiston rod top 126, if appropriate) are maintained to provide support tothe user and reduce compressive forces on the user's spine or otherjoint.

FIG. 5 illustrates an exemplary valve assembly 150 of traction device10. Valve assembly 150 may be used to connect multiple lifting mechanism18 to a pump used to pump air or any other appropriate fluid intolifting mechanism 18. For example the multiple lifting mechanisms 18 oftraction device 10 may be connected to a pump in series or in parallelby appropriately connecting inlets 134. For example, a hose may becoupled between valve assembly 150 (as described below) and a firstinlet 134 of a first lifting mechanism 18. Another hose may be coupledbetween a second inlet 134 of the first lifting mechanism 18 (asillustrated in FIG. 4C, each lifting mechanism 18 may have multipleinlets 134) and a first inlet 134 of a second lifting mechanism 18. Sucha pattern may be continued until each lifting mechanism 18 is eitherconnected to another lifting mechanism 18 or to valve assembly 150. Apump may then be coupled to valve assembly 150 to pump air or anotherfluid into the various lifting mechanisms 18, as described below.Alternatively, each lifting mechanism 18 may be individually coupled tovalve assembly 150 or subsets of the lifting mechanism 18 may be coupledin series and then coupled to valve assembly 150. For example, two frontlifting mechanisms 18 may be coupled in series and two back liftingmechanism 18 may be coupled in series separate from the front liftingmechanisms 18.

Valve assembly 150 provides a point at which the various liftingmechanisms 18, no matter how interconnected, may be coupled to a pump.In the illustrated embodiment, valve assembly 150 is formed integrallywith one of the lifting mechanisms 18 of traction device 10. Forexample, a housing 152 of valve assembly 150 may be formed integrallywith a housing 154 of the associated lifting device (housing 154 may beused in place of housing 114, described above). However, valve assembly150 may also be fabricated as a stand-alone device that may beassociated with traction device 10 in any appropriate manner.

Valve assembly 150 includes a valve plate 156 that includes a number ofcouplers 158 to which hoses may be coupled. For example, a hose from apump may be coupled to coupler 158 a, which is located in the center ofplate 156. Similarly, hoses leading to one or more lifting mechanisms 18or other devices to which air or another fluid is to be supplied (forexample, a lumbar pillow associated with lower support belt 14) may becoupled to couplers 158 b-158 d. Any appropriate number of couplers 158may be included in valve assembly 150. Plate 156 further includes aseries of holes, with each hole extending from a coupler 158 through,plate 156 to an upper surface 160 of plate 156. Therefore, air oranother fluid may travel from upper surface 160 of plate 156 througheach of these holes to a hose attached to the respective coupler 158,and vice versa. When assembled, plate 156 is positioned concentric toand proximate a plunger 162 and is separated from plunger 162 by anumber of O-rings 164 or other appropriate seals. Each O-ring 164 ispositioned around a respective hole in plate 156. Plunger 162 includes acenter hole 166 that extends through plunger 162 and aligns with acenter hole in plate 156 (extending from coupler 158 a). Plunger 162also includes a side hole 168 that extends through plunger 162 and islocated the same distance from the center of plunger 162 as the distancethe holes associated with couplers 158 b-158 d are located from thecenter of plate 156.

A spring 170 is positioned between plunger 162 and an upper innersurface 172 of housing 152. Spring 172 applies a force to plunger 162that causes plunger to be pressed against and form a seal with plate 156(with the aid of O-rings 164). An airtight enclosure is formed in thetop portion of housing 152 above plunger 162 by coupling plate 156 tohousing 152, for example, with one or more appropriate fasteners.Plunger 162 is coupled to a valve lever 174, which is located outside ofhousing 152. Lever 174 may be used to rotate plunger 162 or to raiseplunger 162 so as to break the seal between plunger 162 and plate 156.Furthermore, an airtight enclosure is formed between plate 156 andplunger 172 by fastening plate 156 against a lip 176 of housing 152. Forexample, holes 178 may be used to fasten plate 156 against lip 176 usingscrews or other appropriate fasteners.

When plunger 162 is in contact with plate 156, air or another fluid froma pump coupled to coupler 158 a may pass through plate 156 (in the holeassociated with coupler 158 a) and then through hole 166 of plunger 162into the airtight enclosure above plunger 162. The air or other fluidthen travels back down through hole 168 of plunger 162. Where the airtravels after this depends on where hole 168 is positioned. Lever 174may be used to rotate plunger 162 such that hole 168 may be aligned witha hole in plate 156 corresponding to coupler 158 b, 158 c, or 158 d.When hole 168 is aligned with one of these holes in plate 156, the airmay then travel through the hole in plate 156 to the hose attached tothe corresponding coupler 158 b, 158 c, or 158 d. The air then travelsthrough the corresponding hose to the one or more lifting mechanisms 18or other pressurized devices attached to the hose.

This process may be repeated for the devices coupled to each coupler 158b-158 d by rotating plunger 162 so that hole 168 is aligned with theappropriate hole in plate 156. A check valve may be included in plunger162 in-line with hole 166 to prevent air or another fluid from thevarious attached pressurized devices from returning through hole 166 andthus escaping through the hole in plate 156 corresponding with coupler158 a, for example, when no pump is coupled to coupler 158 a. When auser desires to release the air or another fluid from the variousattached pressurized devices, the user may use lever 174 to lift plunger162 off of plate 156. When this happens, the air or other fluid fromeach of the devices passes from the various hoses coupled to couplers158 b-158 d through plate 156 and then back through plate 156 throughthe hole associated with coupler 158 a (if a pump is not coupled tocoupler 158 a) or through another suitable outlet.

FIG. 6A illustrates an example back belt 28 included in a support belt14 of traction device 10, viewed from the rear. Back belt 28 may becoupled to front belts 31 of support belt 14 using holes 32 and 34 andan associated connector, as illustrated in FIG. 2, with strap 202 beinginternal to plate 204 (closer to the user's body) to accommodate liftingmechanisms 18. However, it should be noted that support belt 14 mayinclude a single belt that includes the features of both back belt 28and front belts 31. Back belt 28 includes a strap 202 and a plate 204.FIG. 6B illustrates strap 202 without plate 204 to more clearlyillustrate strap 202. As described above, plate 204 includes notches 36that are used to connect lifting mechanisms 18 to support belts 14 and16. For example, clips 132 of a lifting mechanism 18 may be insertedinto notches 36 to attach the lifting mechanism 18 to support belt 14.In the example embodiment, strap 202 is coupled to plate 204 at twopivots 206. Pivots 206, along with a canting mechanism 208 incorporatedin strap 202, allow strap 202 to move in relation to plate 204 (and thusin relation to lifting mechanisms 18) to assist in fitting support belts14 and 16 to the user's body, as described below. Any appropriatecomponent may be used to couple strap 202 and plate 204 at pivots 206 soas to allow strap 202 and plate 204 to rotate relative to one another atpivots 206.

Strap 202 includes a first portion 210 a and a second portion 210 b thatare coupled using canting mechanism 208. In one embodiment, cantingmechanism 208 includes two hinges 212 a and 212 b. Plate 204 and cantingmechanism 208 are typically positioned on the user's back near the spinewhen traction device 10 is worn by the user. Portions 210 typicallyextend from the user's back and around the user's sides to the user'sfront. When worn in such a manner, pivots 206 and hinges 212 of cantingmechanism 208 allow portions 210 to conform to the contours of theuser's body, and particularly to the areas of the thorax and the pelvis.Therefore, canting mechanism 208 may be used to more closely fit supportbelts 14 and 16 to users having a variety of different sizes and shapes,while maintaining substantial symmetry and more effective treatment.

As is illustrated in FIGS. 6A and 6B, portions 210 and canting mechanism208 may be integrally formed. For example, portions 210 and cantingmechanism 208 may be formed from a single piece of plastic and hinges212 may be formed by molding or cutting this piece of plastic into thedesired shape. Alternatively, any other suitable method of fabricatingthese components from any appropriate material may be used. Hinges 212 aand 212 b may be formed by forming or cutting slots 214 a and 214 b,respectively, in strap 202. The term “slots” is meant to include bothslits and wedges formed in strap 202. If slits are formed, the slits arepulled open to create wedges when strap 202 is coupled to plate 204. Asillustrated in FIG. 6B, slot 214 a associated with hinge 212 a begins ata first edge 216 of strap 102 and extends almost to a second edge 218 ofstrap 202. The remaining material of strap 202 between the end of slot214 a and second edge 218 of strap 202 forms hinge 212 a. Furthermore, acircular or other cut-out may be formed at the end of slot 214 a nearsecond edge 218 to aid in the opening of slot 214 and to reduce theresultant stresses on hinge 212 a. Slot 214 b is formed in a similarmanner except that slot 214 b begins at second edge 218 of strap 202 andextends almost to first edge 216 of strap 202. Hinge 212 b is locatedproximate to first edge 216 and provides a different point of rotationthan hinge 212 a. Therefore, hinges 212 a and 212 b may be collectivelyreferred to as a polycentric hinge.

If slots 214 are formed as wedges in strap 202, the width of wedges 214and the angle at which wedges 214 are formed determines, at least inpart, the range of movement of portions 210. For example, the greaterthe size of wedges 214, the more range of movement that will be allowed.If slots 214 are formed as slits, the slits are opened to form wedgeshaving an appropriate size. Furthermore, the positioning of hinges 212ensures that the movement of portions 210 is complementary. For example,if an end 220 a of portion 210 a moves up, then an end 220 b of portion210 b will move up a substantially equal amount. This is because theupward movement of end 220 a will cause slot 214 a to close about hinge212 a, and this closure of hinge 214 a will in turn cause slot 214 b toopen about hinge 212 b (due to forces applied and the positioning ofpivots 206). This closure of hinge 214 b will in turn cause an upwardmovement of end 220 b. Therefore, the design of canting mechanism 208allows for the movement of portions 210 a and 210 b of strap 202 andsynchronizes this movement.

Referring again to FIG. 6A, depending upon which part of the user's bodythat back belt 200 is to be positioned around, one or more limitors 222may be used to limit the movement of portions 210 in a certaindirection. For example, if back belt 200 is to be positioned around theuser's hips with first edge 216 of strap 202 nearest to the user's legs,then limitors 222 may be positioned as illustrated to allow portions 210to move upward to accommodate the user's hips, but not allow downwardmovement of portions 210 past a certain point. Limitor slots 224 may beformed in strap 202 and may be configured and positioned such that whenportions 210 are moved downward, limitor slots 224 engage with limitors222 on plate 204 and prevent further downward movement of portions 210with respect to plate 204. In this case, limitors 222 may be peg-likeextensions from plate 204 on the side of plate 204 to which strap 202 isattached. Although limiting the downward movement of portions 210 isdescribed, it should be understood that limitors 222 and limitor slots224 may be positioned in other embodiments so as to limit the upwardand/or downward movement of portions 210.

FIG. 7 illustrates another example back belt 300 included in a supportbelt 14 of traction device 10. Back belt 300 includes a strap having twoseparate portions 302 a and 302 b and also includes a plate 304 couplingportions 302 a and 302 b. As with plate 204, lifting mechanisms 18 arecoupled to plate 304. Portions 302 are coupled to plate 304 at pivots306, such that portions 302 may move independently of plate 304. Backbelt 300 also includes a canting mechanism 308. However, unlike cantingmechanism 208 of FIGS. 6A and 6B, canting mechanism 308 is implementedusing a series of gears. In one embodiment, these gears include strapgears 310 a and 310 b which are rotatably coupled to portions 302 a and302 b, respectively, and plate gears 312 a and 312 b which are rotatablycoupled to plate 304. Gears 310 and 312 may be fabricated from plastic,metal, or any other appropriate material.

Gears 310 and 312 may be coupled to one another in the following manner.Gear 310 a meshes with gear 312 a, gear 312 a meshes with gear 312 b,and gear 312 b meshes with gear 310 b. Therefore, if gear 310 a isrotated, this rotation also causes gears 312 a, 312 b, and 310 b torotate. Gears 310 a and 310 b are coupled to portions 302 a and 302 b,respectively, such that when a portion 302 rotates about its respectivepivots 306, the respective strap gear 310 associated with the portion302 also rotates about the pivot 306. Since gears 310 are coupledthrough gears 312, if one portion 302 is moved upward or downward, theother portion 302 moves substantially the same distance in the samedirection.

For example, if an end 320 a of portion 302 a is raised (for example, tofit over a user's hip), then this motion will cause gear 310 a to rotatein a clockwise direction and the degree of this rotation will berelative to the distance that end 320 a raised. The clockwise rotationof gear 310 a will in turn cause a counter-clockwise rotation of gear312 a, and this rotation of gear 312 a will cause a clockwise rotationof gear 312 b. Finally, the clockwise rotation of gear 312 b will causea counter-clockwise rotation of gear 310 b, which in torn will chase anend 320 b of portion 302 b to move substantially the same distanceupward as end 320 a was moved. Furthermore, although not illustrated inFIG. 7, back belt 300 may have limitors and limitor slots (as with backbelt 200) to limit the movement of straps 302 a and 302 b in one or moredirections, as described with reference to FIGS. 6A and 6B above.Moreover, although two example canting mechanisms for facilitating themanipulation of a support belt 14 to fit the contours of a user's bodywhile maintaining substantial symmetry are described, any otherappropriate mechanisms may be used and are included within the scope ofthe present invention.

FIG. 8 is a schematic diagram illustrating portions of upper supportbelt 14 of traction device 10 of FIGS. 1A through 1C, illustrating themovable relationship between front belts 30 a, 30 b and back belt 28.Front belts 30 a and 30 b may be adjusted relative to back belt 28 toappropriately fit a user. Adjustment of front belts 30 a and 30 b withrespect to back belt 28 is referred to as a macro adjustment becauseadditional adjustments may be made through latches 24 and 26 and commonstrap 22. Lower belt 16 may be adjusted in a similar manner.

In the illustrated embodiment, back belt 28 is formed with a pair ofholes 32 for intermeshing and coupling with one of holes 33 formed infront belts 30 a and 30 b. Use of holes 32 and 33 may sometimes allowsuitable adjustments of front portions 30 a and 30 b such that a usermay pull on both 30 a and 30 b and increase the length equally from bothsides; however it is often difficult to ensure that front belts 30 a and30 b have been lengthened by the same number of holes 33. In addition,in embodiments that do not utilize holes 32 and 33, such as embodimentsthat utilize clamps or other suitable connecting mechanisms for joiningfront belts 30 a and 30 b to back belt 28, it is often difficult tolengthen belt 14 equally from both sides. If upper belt 14 is notlengthened equally from both sides, this may skew the position oflifting mechanisms 18 to an undesired position. Therefore, an adjustmentmechanism is provided that facilitates lengthening belt 14 to a suitablesize but maintains the appropriate orientation of the associated liftmechanisms 18. An example embodiment of such a mechanism is describedbelow in conjunction with FIGS. 9A through 9C.

FIG. 9A is a top view of a belt 402 in combination with an adjustmentmechanism 404 according to the teachings of the invention. Belt 402 maybe similar to upper belt 14 or lower belt 16 and includes front portions406 a and 406 b that may be connected to a back portion 408. Belt 402 islengthened by pulling together front portions 406 a and 406 b thuspulling the front portions away from back portion 408. As describedabove, it is often difficult to pull equally on front portion 406 a and406 b to maintain the desired orientation of belt 402 about the body ofa user. When utilizing lift mechanisms 18, this disorientation couldresult in improper fitting of the belt and improper forces being appliedto the user. Therefore, an adjustment mechanism 404 is provided.Adjustment mechanism 404 includes a strap 409 having ends 410 and 412coupled to front portions 406 a and 406 b, respectively. As used herein,“ends” refers generally to opposite portions of strap 409; however, ends410 and 412 are not required to be the termination of strap 409. Ends410 and 412 may couple to front portions 406 a and 406 b, respectivelythrough any suitable manner, such as snap combinations 414, 426 and 416,428. Adjustment mechanism 408 also includes a clamp 420 coupled to backbelt 408 through snap combination 424, 434. Clamp 420 includes rollersor bars 422 that guide strap 409 along back belt 408. A hook and loopmaterial, commonly known as Velcro, is formed on strap 409 betweenrollers 422, as denoted by reference numeral 418. Strap 409 may alsoinclude this hook and loop material on other portions of it. Operationof adjustment mechanism 408 is described with reference to FIG. 9B.

FIG. 9B is a top view of the belt and adjustment mechanism 408 and belt402 of FIG. 9A showing belt 402 in an adjusted position. As shown, frontportions 406 a and 406 b have been pulled together, as denoted byreference numeral 448, thus increasing the length of belt 402. Pullingfront portions 406 a and 406 b together necessarily pulls strap 409 andhook and loop portion 418 along with it. In doing so, hook and loopportion 418 detaches from each other, which causes strap 409 to bepulled equally from both the side of 406 a and the side of 406 b. Thisensures that the resulting configuration of belt 402 maintains theproper orientation for lift mechanisms such as those described above.Front belts 406 a, 406 b may then be secured to back belt 408 by rivetsor other suitable connectors 450 and 452.

FIG. 9C is a top view of the belt 402 shown in FIGS. 9A and 9B afterdetachment of adjustment mechanism 404. After belt 402 is suitablyadjusted, as described in FIG. 9B, adjustment mechanism 404 may bedetached at ends 410 and 412 as well as clamp 420, leaving the device asshown in FIG. 9C. Thus a macro adjustment for belt 402 may be effectedthat ensures proper orientation of associated lifting mechanisms, whilefine tuning of the fit or belt may be accomplished through common strap22 and locking devices 20.

Although the present invention has been described with severalembodiments, numerous changes, substitutions, variations, alterations,and modifications may be suggested to one skilled in the art, and it isintended that the invention encompass all such changes, substitutions,variations, alterations, and modifications as fall within the spirit andscope of the appended claims.

What is claimed is:
 1. An ambulatory traction device, comprising: afirst support configured to be positioned on a user's body; a secondsupport configured to be positioned on the users body such that aportion of the user's body is positioned between the first and secondsupports; and one or more lifting mechanisms each coupling the supportsand operable to apply a decompressive force to the portion of the user'sbody when the supports are positioned on the, user's body, each liftingmechanism comprising: a sleeve having a non-circular cross-section andoperable to contain a fluid; and a piston configured to move within thesleeve in response to an increase in fluid pressure within the sleeve.2. The device of claim 1, wherein the device is an ambulatory spinaltraction device, the supports are support belts, and the portion of theuser's body comprises at least a portion of the user's spine.
 3. Thedevice of claim 1, wherein the piston comprises a non-circular flangeadapted to seal against the sleeve and the lifting mechanism furthercomprises a housing conformed to the sleeve, the housing preventing theflange from exiting the sleeve, the sleeve, housing, and flangecollectively forming a substantially fluid-tight enclosure.
 4. Thedevice of claim 3, wherein the sleeve is fabricated from a non-plasticmaterial and the housing is fabricated from a plastic material.
 5. Thedevice of claim 3, wherein: the piston comprises a piston rod and aflange adapted to seal against the sleeve; and the housing defines anopening through which the piston rod may move, but through which theflange may not move.
 6. The device of claim 3, wherein: the housing hasan interior height between a first location substantially near a bottomof the housing and a second location substantially near a top of thehousing; and the flange of the piston is operable to travel over theentire interior height depending on the fluid pressure within thesleeve, the flange of the piston being located at the first locationsubstantially near the bottom of the housing when the fluid pressurewithin the sleeve is at its minimum, the flange of the piston beinglocated at the second location substantially near the top of the housingwhen the fluid pressure within the sleeve is at its maximum.
 7. Thedevice of claim 3, wherein the housing comprises one or more inletspositioned such that a fluid may be pumped through the inlets into thesubstantially fluid-tight enclosure.
 8. The device of claim 1, whereinthe piston comprises a flange adapted to seal against the sleeve and thelifting mechanism further comprises a piston ring configured to surrounda perimeter of the flange to assist in forming a substantiallyfluid-tight seal between the flange and the sleeve.
 9. The device ofclaim 1, wherein the piston defines a cavity fluidly coupled to aninterior of the sleeve and extending through the piston.
 10. The deviceof claim 9, wherein the lifting mechanism further comprises an elasticmember positioned in the cavity and coupled to the piston, the elasticmember operable to refract the piston in response to a decrease in fluidpressure within the sleeve.
 11. The device of claim 10, wherein theelastic member comprises a spring.
 12. The device of claim 10: whereinthe housing has an interior height between a first locationsubstantially near a bottom of the housing and a second locationsubstantially near a top of the housing; and wherein, as a result of theelastic member positioned within the cavity of the piston, the piston isoperable to travel over the entire interior height depending on thefluid pressure within the sleeve, the piston being located at the firstlocation substantially near the bottom of the housing when the fluidpressure within the sleeve is at its minimum, the piston being locatedat the second location substantially near the top of the housing whenthe fluid pressure within the sleeve is at its maximum.
 13. The deviceof claim 10, wherein: the housing has a height; the piston has a maximumamount of extension from the housing; and the lifting mechanism has amaximum height that is substantially equivalent to the height of thehousing plus the maximum amount of extension of the piston.
 14. Alifting mechanism for use with an ambulatory traction device, thelifting mechanism configured to be coupled between two supports of thetraction device such that a portion of a user's body is positionedbetween the supports, the lifting mechanism operable to apply adecompressive force to the portion of the user's body when the supportsare positioned on the user's body, the lifting mechanism comprising: asleeve having a non-circular cross-section and operable to contain afluid; and a piston configured to move within the sleeve in response toan increase in fluid pressure within the sleeve.
 15. The liftingmechanism of claim 14, wherein the ambulatory traction device is anambulatory spinal traction device, the supports are support belts, andthe portion of the user's body comprises at least a portion of theuser's spine.
 16. The lifting mechanism of claim 14, wherein the pistoncomprises a non-circular flange adapted to seal against the sleeve andthe lifting mechanism further comprises a housing conformed to thesleeve, the housing preventing the flange from exiting the sleeve, thesleeve, housing, and flange collectively forming a substantiallyfluid-tight enclosure.
 17. The lifting mechanism of claim 16, whereinthe sleeve is fabricated from a non-plastic material and the housing isfabricated from a plastic material.
 18. The lifting mechanism of claim16, wherein: the piston comprises a piston rod and a flange adapted toseal against the sleeve; and the housing defines an opening throughwhich the piston rod may move, but through which the flange may notmove.
 19. The lifting mechanism of claim 16, wherein: the housing has aninterior height between a first location substantially near a bottom ofthe housing and a second location substantially near a top of thehousing; and the flange of the piston is operable to travel over theentire interior height depending on the fluid pressure within thesleeve, the flange of the piston being located at the first locationsubstantially near the bottom of the housing when the fluid pressurewithin the sleeve is at its minimum, the flange of the piston beinglocated at the second location substantially near the top of the housingwhen the fluid pressure within the sleeve is at its maximum.
 20. Thelifting mechanism of claim 16, wherein the housing comprises one or moreinlets positioned such that a fluid may be pumped through the inletsinto the substantially fluid-tight enclosure.
 21. The lifting mechanismof claim 14, wherein the piston comprises a flange adapted to sealagainst the sleeve and the lifting mechanism further comprises a pistonring configured to be positioned around a perimeter of the flange toassist in forming a substantially fluid-tight seal between the flangeand the sleeve.
 22. The lifting mechanism of claim 14, wherein thepiston defines a cavity fluidly coupled to an interior of the sleeve andextending through the piston.
 23. The lifting mechanism of claim 22,further comprising an elastic member positioned in the cavity andcoupled to the piston, the elastic member operable to retract the pistonin response to a decrease in fluid pressure within the sleeve.
 24. Thetilling mechanism of claim 23, wherein the elastic member comprises aspring.
 25. The lifting mechanism of claim 23: wherein the housing hasan interior height between a first location substantially near a bottomof the housing and a second location substantially near a top of thehousing; and wherein, as a result of the elastic member positionedwithin the cavity of the piston, the piston is operable to travel overthe entire interior height depending on the fluid pressure within thesleeve, the piston being located at the first location substantiallynear the bottom of the housing when the fluid pressure within the sleeveis at its minimum, the piston being located at the second locationsubstantially near the top of the housing when the fluid pressure withinthe sleeve is at its maximum.
 26. The lifting mechanism of claim 23,wherein: the housing has a height; the piston has a maximum amount ofextension from the housing; and the lifting mechanism has a maximumheight that is substantially equivalent to the height of the housingplus the maximum amount of extension of the piston.
 27. A liftingmechanism for use with an ambulatory traction device, the liftingmechanism configured to be coupled between two supports of the tractiondevice such that a joint of the user is positioned between the supports,the lifting mechanism operable to apply a decompressive force to thejoint when the supports are positioned on the user's body, the liftingmechanism comprising: a sleeve operable to contain a fluid; a pistonconfigured to move within the sleeve in response to an increase in fluidpressure within the sleeve, the piston having a flange adapted to sealagainst the sleeve, the piston defining a cavity fluidly coupled to aninterior of the sleeve and extending through the piston including theflange; a housing conformed to the sleeve and preventing the flange ofthe piston from exiting the sleeve, the housing having an interiorheight between a first location substantially near a bottom of thehousing and a second location substantially near a top of the housing,the housing, sleeve, and flange of the piston collectively forming asubstantially fluid-tight enclosure; and an elastic member coupled tothe piston and positioned within the cavity of the piston including theflange, the elastic member operable to retract the piston in response toa decrease in fluid pressure within the sleeve; the piston beingoperable as a result of the elastic member positioned within the cavityof the piston including the flange to travel over the entire interiorheight of the housing depending on the fluid pressure within the sleeve,the flange of the piston being located at the first locationsubstantially near the bottom of the housing when the fluid pressurewithin the sleeve is at its minimum, the flange of the piston beinglocated at the second location substantially near the top of the housingwhen the fluid pressure within the sleeve is at its maximum.
 28. Thelifting mechanism of claim 27, wherein the ambulatory traction device isan ambulatory spinal traction device, the supports are support belts,and the joint comprises at least a portion of the user's spine.
 29. Thelifting mechanism of claim 27, wherein the elastic member comprises aspring.
 30. The lifting mechanism of claim 27, wherein: the piston has amaximum amount of extension from the housing; and the lifting mechanismhas a maximum height that is substantially equivalent to the interiorheight of the housing plus the maximum amount of extension of thepiston.
 31. The lifting mechanism of claim 27, wherein the sleeve andthe flange of piston each have substantially elliptical, non-circularcross-sections.
 32. A lifting mechanism for use with an ambulatorytraction device, the lifting mechanism configured to be coupled betweentwo supports of the traction device such that a joint of the user ispositioned between the supports, the lifting mechanism operable to applya decompressive force to the joint when the supports are positioned onthe user's body, the lifting mechanism comprising: a sleeve operable tocontain a fluid; a piston configured to move within the sleeve inresponse to an increase in fluid pressure within the sleeve, the pistonhaving a flange adapted to seal against the sleeve, the piston defininga cavity fluidly coupled to an interior of the sleeve and extendingthrough the piston including the flange; a housing conformed to thesleeve and preventing the flange of the piston from exiting the sleeve,the housing having an interior height between a first locationsubstantially near a bottom of the housing and a second locationsubstantially near a top of the housing, the housing, sleeve, and flangeof the piston collectively forming a substantially fluid-tightenclosure; and means, positioned within the cavity of the pistonincluding the flange, for retracting the piston in response to adecrease in fluid pressure within the sleeve; the piston being operableas a result of the means for retracting to travel over the entireinterior height of the housing depending on the fluid pressure withinthe sleeve, the flange of the piston being located at the first locationsubstantially near the bottom of the housing when the fluid pressurewithin the sleeve is at its minimum, the flange of the piston beinglocated at the second location substantially near the top of the housingwhen the fluid pressure within the sleeve is at its maximum.
 33. Anambulatory traction device, comprising: a first support belt configuredto be positioned on a user's body, the first support belt comprising aplurality of first notches fanned in the first belt, each first notchconfigured to receive and secure a first clip of a lifting mechanism,the first support belt comprising a plurality of first semicircularslots formed in the first support belt, each first semicircular slotbeing curved in a first direction away from the lifting mechanism and atleast partially surrounding a corresponding first notch; a secondsupport belt configured to be positioned on the user's body spaced apartfrom the first support such that a joint of the user's body ispositioned between the first and second supports, the second supportbelt comprising a plurality of second notches formed in the second belt,each second notch configured to receive and secure a second clip of alifting mechanism, the second support belt comprising a plurality ofsecond semicircular slots formed in the second support bolt, each secondsemicircular slot being curved in a first direction away from thelifting mechanism and at least partially surrounding a correspondingsecond notch; and a plurality of lifting mechanisms coupled between thesupport belts and operable to apply a decompressive force to the jointwhen the support belts are positioned on the user's body, each liftingmechanism comprising: a first clip located near a first end of thelifting mechanism and configured to be inserted through and secured tothe first support belt using one of the first notches, the correspondingfirst semicircular slot of the first support belt allowing the first endof the lifting mechanism to rotate generally transverse to a surface ofthe first support belt adjacent the user's body; and a second cliplocated near a second end of the lifting mechanism and configured to beinserted through and secured to the second support belt using one of thesecond notches, the corresponding second semicircular slot of the secondsupport belt allowing the second end of the lifting mechanism to rotategenerally transverse to a surface of the second support belt adjacentthe user's body, the first and second semicircular slots beingconfigured such that rotation of the first end of the lifting mechanismgenerally transverse to the surface of the first support belt towards oraway from the user requires rotation of the second end of the liftingmechanism generally transverse to the surface of the second support beltaway from or towards the user, respectively.
 34. The device of claim 33,wherein the device is an ambulatory spinal traction device and the jointcomprises at least a portion of the user's spine.
 35. The device ofclaim 33, wherein the first and second notches each comprise asubstantially semi-circular shaped side curving in a direction generallyaway from the corresponding lifting mechanism.
 36. The device of claim33, wherein each slot is enlarged into a substantially circular openingat each of its ends.
 37. The device of claim 33, wherein the liftingmechanism further comprises: a sleeve having a non-circularcross-section and operable to contain a fluid; a piston configured tomove within the sleeve in response to an increase in fluid pressurewithin the sleeve, the piston comprising a noncircular flange adapted toseal against the sleeve; and a housing conformed to the sleeve andpreventing the flange of the piston from exiting the sleeve in responseto an increase in fluid pressure within the sleeve, the sleeve, housing,and flange collectively forming a substantially fluid-tight enclosure.38. A lifting mechanism for use with an ambulatory traction device, thelifting mechanism configured to be coupled between two supports of thetraction device such that a joint of a user is positioned between thesupports, the lifting mechanism operable to apply a decompressive forceto the joint when the supports are positioned on the user's body, thelifting mechanism comprising: a sleeve having a non-circularcross-section and operable to contain a fluid; a piston comprising anon-circular flange configured to be positioned inside of and to movewithin the sleeve in response to fluid pressure being applied againstthe flange; a housing bottom comprising a seal; and a housing topcoupled to the housing bottom to define a housing conformed to thesleeve and preventing the flange from exiting the sleeve, coupling ofthe housing top to the housing bottom urging the sleeve into a sealingrelationship with the seal of the housing bottom such that the sleeve,housing, and flange thereafter collectively form a substantiallyfluid-tight enclosure.
 39. The lifting mechanism of claim 38, whereinthe sleeve is fabricated from a non-plastic material and the housing isfabricated from a plastic material.
 40. The lifting mechanism of claim38, wherein the housing comprises one or more inlets, the inletspositioned such that air may be pumped through the inlets into thesubstantially fluid-tight enclosure.
 41. The lifting mechanism of claim38, wherein the elastic member comprises a spring.
 42. The liftingmechanism of claim 38, wherein: the housing has an interior heightbetween a first location substantially near a bottom of the housing anda second location substantially near a top of the housing; and theflange of the piston is operable to travel over the entire interiorheight depending on the fluid pressure within the sleeve, the flange ofthe piston being located at the first location substantially near thebottom of the housing when the fluid pressure within the sleeve is atits minimum, the flange of the piston being located at the secondlocation substantially near the top of the housing when the fluidpressure within the sleeve is at its maximum.
 43. The lifting mechanismof claim 38, wherein: the piston further comprises a piston rod defininga cavity fluidly coupled to an interior of the sleeve and extendingthrough the flange of the piston; the housing defines an opening throughwhich the piston rod may move, but through which the flange may notmove; and the lifting mechanism further comprises an elastic memberpositioned in the cavity of the piston rod, the elastic member coupledbetween the piston rod and the housing and extending through the flange,the elastic member operable to retract the piston in response to adecrease in fluid pressure within the sleeve.
 44. The lifting mechanismof claim 43, wherein: the housing has a height; the piston rod has amaximum amount of extension from the housing; and the lifting mechanismhas a maximum height that is substantially equivalent to the height ofthe housing plus the maximum amount of extension of the piston rod.